Method findEdge

src/data-structures/graph/Graph.js:122–130

* @param {GraphVertex} startVertex * @param {GraphVertex} endVertex * @return {(GraphEdge|null)}

(startVertex, endVertex)

   * @return {(GraphEdge|null)}
   */
  findEdge(startVertex, endVertex) {
    const vertex = this.getVertexByKey(startVertex.getKey());

    if (!vertex) {
      return null;
    }

    return vertex.findEdge(endVertex);
  }

  /**
   * @return {number}